Opinion: + to skill levels are too dominant
All my recent 5 caster staff upgrades has had to have the "+ to skill levels" modifier. Like there are ton of different other ways it can be good, but if that skill level modifier is missing, then unfortunately it is not an upgrade. Feels way too mandatory on weapons, because they roll so high. Would probably suffice for me if their max roll was a lot lower. For example up to 2 in 1-handers, and up to 3 in 2-handers.
I'm saying this because the unique weapons are not really doing it for me, because I would be sacrificing so much damage for them. But that has been my experience as a elemental Blood Mage spellcaster.
Don't get me wrong, it is great to have powerful mods to chase, but this one just rolls too high in my opinion. It kinda hurts build diversity by limiting viable options imho.